Light Meter Research Articles

Development and validation of a 'MyLyt' wearable light tracking device.

We developed a clip-on light tracker (MyLyt) for estimating light exposure in real time. This study aimed at validating and investigating the feasibility of using MyLyt in children and adults. The study was conducted in two phases. Phase 1 involved validation against a factory-calibrated digital lux meter in three separate conditions: controlled environmental set-up, outdoors and indoors where intra-test (two measurements by the same tracker), inter-test (measurements among trackers) and inter-device (MyLyt tracker and lux meter) validations were conducted. Phase 2 involved a feasibility study where MyLyt was used in a real-world setting by 21 adults and 8 children. Participants were asked to log their real-time movements in an 'activity diary', which were correlated with the lux levels measured by the tracker. A strong positive correlation and non-significant difference in the recorded mean illuminance levels were observed during intra-test (inter-class correlation: 1.00, p=0.99), inter-test (0.91-1.00, p > 0.15) and inter-device (0.91-1.00, p > 0.56) validation in all three testing conditions (p > 0.49), except the indoor location. While the lux level measured by MyLyt was significantly higher than that of the lux meter (p < 0.01) in the indoor locations, differences were minimal and clinically insignificant. A Bland-Altman plot showed a minimal mean difference (95% limits of agreement) between the MyLyt tracker and lux meter in all three conditions (controlled environmental set-up: 641 [-949, 2230], outdoor: 74 [-2772, 2920] and indoor: -35 [-151, 80]lux). Phase 2 validation showed an expected illuminance level against the corresponding location with high sensitivity (97.8%) and specificity (99%) to accurately differentiate between outdoor and indoor locations. The MyLyt tracker showed good repeatability, strong correlation and comparable values with the lux meter in the three tested conditions, making it suitable for tracking light exposure patterns for both research and clinical purposes.

Brighter Time: A Smartphone App Recording Cognitive Task Performance and Illuminance in Everyday Life.

Light is an influential regulator of behavioural and physiological state in mammals. Features of cognitive performance such as memory, vigilance and alertness can be altered by bright light exposure under laboratory and field conditions. However, the importance of light as a regulator of performance in everyday life is hard to assess and has so far remained largely unclear. We set out to address this uncertainty by developing a tool to capture measures of cognitive performance and light exposure, at scale, and during everyday life. To this end, we generated an app (Brighter Time) which incorporated a psychomotor vigilance (PVT), an N-back and a visual search task with questionnaire-based assessments of demographic characteristics, general health, chronotype and sleep. The app also measured illuminance during task completion using the smartphone’s intrinsic light meter. We undertook a pilot feasibility study of Brighter Time based on 91-week-long acquisition phases within a convenience sample (recruited by local advertisements and word of mouth) running Brighter Time on their own smartphones over two study phases in winter and summer. Study compliance was suitable (median = 20/21 requested task completions per subject). Statistically significant associations were observed between subjective sleepiness and performance in all tasks. Significant daily variations in PVT and visual search performance were also observed. Higher illuminance was associated with reduced reaction time and lower inverse efficiency score in the visual search. Brighter Time thus represents a viable option for large-scale collection of cognitive task data in everyday life, and is able to reveal associations between task performance and sleepiness, time of day and current illuminance. Brighter Time’s utility could be extended to exploring associations with longer-term patterns of light exposure and/or other light metrics by integrating with wearable light meters.

Analysis of the Effectiveness of Solar Cell Voltage Based on the Angle of Exposure to Sunlight

Solar Power Plant is a system that is able to convert solar energy into electrical energy, it is incorporated in several components in the form of solar panels (photovoltaic), battery testing (solar charger controller), inverter, battery, Lux Meter and other accessories. In order to get the maximum voltage, current, and power results, it is necessary to place the solar panels correctly, by determining the angle of inclination according to previous research, and measuring the angle of inclination based on the equator. In this study, solar cells are expected to get the maximum voltage (Volt), Current (Ampere), and Power (Watt) so that solar cells can be applied optimally in the Ponorogo Regency area. This research is to determine the Tilt Angle of the Solar Panel, Voltage (Volt), Current (Amperes), and Power (Watt). The results showed that the best slope angle was at an angle of 15º to the north, with a power value of 8.23 ​​Watt, and the best absorption of sunlight was obtained during the day at 10.00-11.00 WIB, and the best results were obtained in March 2021.

Evaluation of light transmittance performance of light-transmitting concrete with optical fibre

• Synergistic effects of fibre diameter, fibre spacing and light incidence angle were studied. • LTC specimens were tested for its compressive strength and light transmittance. • The effect of fibre diameter is more significant than fibre spacing. • ANOVA was carried out for compressive strength and light transmittance analysis. • Lower compressive strength may not due to gaps between fibre–matrix interface. Light incidence angle is an important parameter to Light-transmitting Concrete (LTC), especially when it is used for building materials exposed to sunlight. Yet, there is a lack of deeper understanding on the performance of LTC when light incidence is encountered with different angles. This study covers the synergistic effect of light incidence angle, fibre spacing, and fibre diameter on the light transmittance of LTC. Optical fibres with different diameters and spacings are incorporated into the LTC specimen. Light transmittance is measured using a light meter, where the test is conducted in a tight enclosed wooden board. The results show that, as the fibre diameter becomes larger in the LTC, the light transmittance increases. The highest transmittance of 1.613 % was found for LTC with a fibre diameter of 2 mm. In contrast, the light transmittance decreases with the increase in fibre spacing and light incidence angle. It was found that LTC with a 2 mm fibre diameter shows a significant difference with other fibre diameters even at the light incidence angle of 30°. Besides, the effect of fibre diameter on light transmittance was found to be more significant as compared to fibre spacing.

Cyclical Aging Tests in Latex Coating with TiO2 Nanoparticles by UVb Radiation

This study evaluated the properties of adhesion, cracking, rusting, and accumulated irradiance on the surface of four vinyl acrylic resin coatings. QUV accelerated aging technique was applied. The coatings accumulated irradiance in cyclic form and was controlled by the tests of atmospheric temperature and relative humidity. A paper money currency validator counterfeit has been used because of its constant irradiance of 1,41 mW/cm2; a power of 9 W of UV radiation; 220 V, ranging an equipment temperature (OPALUX) between 40 °C and 60 °C. Irradiance has been measured by using the UV light meter equipment model YK-35UV (2 to 20 mW/cm2). Latex coatings embedded with TiO2 nanoparticles and prepared in four different formulations with CaCO3 plus Diatomite were applied on a surface area of 5.5 cm length times 1.5 cm width. The exposition time ranged from 56 to 500 h of irradiance at a period span of eight h each day. Coatings were altered on its properties of adhesion, elasticity and photooxidation on their surface.

Effect of Text Messaging Parents of School-Aged Children on Outdoor Time to Control Myopia

Myopia in school-aged children is a public health issue worldwide; consequently, effective interventions to prevent onset and progression are required. To investigate whether SMS text messages to parents increase light exposure and time outdoors in school-aged children and provide effective myopia control. This randomized clinical trial was conducted in China from May 2017 to May 2018, with participants observed for 3 years. Of 528 965 primary school-aged children from Anyang, 3113 were randomly selected. Of these, 268 grade 2 schoolchildren were selected and randomly assigned to SMS and control groups. Data were analyzed from June to December 2021. Parents of children in the SMS group were sent text messages twice daily for 1 year to take their children outdoors. All children wore portable light meters to record light exposure on 3 randomly selected days (2 weekdays and 1 weekend day) before and after the intervention. The co-primary outcomes were change in axial length (axial elongation) and change in spherical equivalent refraction (myopic shift) from baseline as measured at the end of the intervention and 3 years later. A secondary outcome was myopia prevalence. Of 268 grade 2 schoolchildren, 121 (45.1%) were girls, and the mean (SD) age was 8.4 (0.3) years. Compared with the control group, the SMS intervention group demonstrated greater light exposure and higher time outdoors during weekends, and the intervention had significant effect on axial elongation (coefficient, 0.09; 95% CI, 0.02-0.17; P = .01). Axial elongation was lower in the SMS group than in the control group during the intervention (0.27 mm [95% CI, 0.24-0.30] vs 0.31 mm [95% CI, 0.29-0.34]; P = .03) and at year 2 (0.39 mm [95% CI, 0.35-0.42] vs 0.46 mm [95% CI, 0.42-0.50]; P = .009) and year 3 (0.30 mm [95% CI, 0.27-0.33] vs 0.35 mm [95% CI, 0.33-0.37]; P = .005) after the intervention. Myopic shift was lower in the SMS group than in the control group at year 2 (-0.69 diopters [D] [95% CI, -0.78 to -0.60] vs -0.82 D [95% CI, -0.91 to -0.73]; P = .04) and year 3 (-0.47 D [95% CI, -0.54 to -0.39] vs -0.60 D [95% CI, -0.67 to -0.53]; P = .01) after the intervention, as was myopia prevalence (year 2: 38.3% [51 of 133] vs 51.1% [68 of 133]; year 3: 46.6% [62 of 133] vs 65.4% [87 of 133]). In this randomized clinical trial, SMS text messages to parents resulted in lower axial elongation and myopia progression in schoolchildren over 3 years, possibly through increased outdoor time and light exposure, showing promise for reducing myopia prevalence. Chinese Clinical Trial Registry Identifier: ChiCTR-IOC-17010525.

Measurement of personal radio frequency exposure in Japan: The Hokkaido Study on the Environment and Children's health

The opportunities for exposure to radiofrequency electromagnetic fields (RF-EMF) among children are increasing. Children's exposure to RF-EMF in Japan was recorded using a personal exposure meter (ExpoM-RF), and factors associated with the exposure examined. A total of 101 children, aged 10–15 years old, participated in the prospective birth cohort “Hokkaido study”. RF-EMF data were recorded in the 700 MHz-5.8 GHz frequency range for 3 days. The recorded data were summarized into six groups of frequency bands: downlink from mobile phone base stations (DL), uplink from mobile phones to a base station (UL), Wireless Local Area Network (LAN), terrestrial digital TV broadcasting (digital TV), 2.5 GHz and 3.5 GHz Time Division Duplex (TDD), 1.9 GHz TDD, and total (the summation of power density in all measured frequency bands). A questionnaire was used to document the internet environment (at home) and mobile phone usage. Personal RF-EMF exposure in Japanese children was lower than that reported in studies in Europe. The DL signals from mobile phone base stations were the most significant contributors to total exposure, while Wireless LAN and digital TV were only higher at home. The urban residence was consistently associated with increases in the four groups of frequency bands (DL, UL, digital TV, and TDD). TDD level has several associations with mobile phone usage (calls using mobile phones, video viewing, text message service, and online game). The association between inattention/hyperactivity subscale of the Strengths and Difficulties Questionnaire (SDQ) and higher Wireless LAN exposure at nighttime was also noted. Further studies with additional data will shed light on factors involved in RF-EMF exposure among Japanese children.

Luxmeter Equipped with Proximity Sensor for Operating Lamp Light Calibration in Hospital

The measurement of the operating lamp light on the operating table is very necessary so that the light rays do not glare during surgery and pathological conditions can be recognized easily without any shadows. This study aims to design a tool to measure light intensity equipped with automatic distance measurement. The design of this tool uses an ultrasonic sensor HC-SR04 to measure the distance between the light source and the sensor module and the MAX44009 sensor to measure the light intensity of the operating lamp displayed on the TFT screen. The design of the tool has been tested on operating lamps. In this study, measurements were made on two light sources, namely the GEA brand operating lamp in the Operating Room RSIA Putri Surabaya and lamps in an Electromedical Engineering Workshop on the Surabaya campus. The results of measurements when using a lamp in an electromedical engineering workshop in Surabaya with the distance between the module and the light source using a 75 cm roll meter, it is known that the error value is 0.0127% for a distance of 100 cm as much as 0.0045%. The module error value when measuring the intensity of light between the tool and the lamp in the electromedical engineering workshop with a roll meter distance setting of 75 cm gets an error value of 0.082% lux and at a roll meter distance of 100 cm, the lux error value is 0.055%. The design of a lux meter that is equipped with a proximity sensor can measure the intensity of light and the distance between the device and the light source and can assist in the learning process with a more effective Luxmeter design that will help Electromedical Technician in testing operating lamps in hospitals become more efficient

PSX-B-18 Can a Smartphone be Used for Daily Field Measurements?

Abstract The popularity of smartphones is undeniable in nearly all facets of society, and their use is worldwide spread, the objective of this abstract is to compare two smartphones and some apps to commercial equipment. The study was performed in Campinas, São Paulo, Brazil using GPS, light, and sound sensors, from two smartphones. There were 5 apps tested for each smartphone sensor, and specific methodology for each one, for GPS was used a known length running track, for light and decibel meters was used commercials equipment. For GPS, there was no statistical difference (P&amp;lt; 0.05) between the type of mobile phone and the app tested and there was also no statistical difference (P&amp;lt; 0.05) for the use or non-use of the internet during the measurements. For the decibel meter, different noise levels were tested, and there was a difference between the levels, which was expected. At each noise level, there were statistical differences (P&amp;lt; 0.05) between smartphone type, internet use, and the apps tested. In this summary, it will not be possible to show all these results. For the light meter, there was a significant difference between the application and the lux level, regardless of the type of smartphone. At 300 lux the applications were the same as the control. At 600 lux only the "Light meter" (My Mobile Tools developer) app had results equal to the control. At 1000 lux measurements, all applications were different from the control. The internet and lux interaction were the same for the averages of the 300 and 600 lux levels, with 1000 lux the use of the internet favored the readings. The use of cell phones can be a cheap and practical alternative for daily measurements on rural properties, to ensure the sustainability of the systems and labor health.

Associations between indoor light pollution and unhealthy outcomes in 2,947 adults: Cross-sectional analysis in the HEIJO-KYO cohort

Nighttime use of artificial light is usual and essential in these modern times. Although light exposure at night (LAN) is reportedly a risk factor of several diseases, epidemiological studies on indoor LAN levels are still limited. Hence, the present study aimed to measure bedroom LAN levels by using light meters in a larger sample than in previous studies, and to evaluate the associations with comprehensive health outcomes. Out of 3012 participants, 2947 (mean age, 69.3 years; female, 60.6%) completed the bedroom LAN intensity measurement. The median bedroom LAN intensity was 1.0 lux (interquartile range, 0.2–4.0 lux). In a multivariable analysis adjusted for potential confounding factors, the highest quartile group of bedroom LAN intensity had significantly higher body weight, body mass index, abdominal circumference, and low-density lipoprotein cholesterol than the lowest quartile group. The group with a median LAN intensity ≥10 lux had significantly higher white blood cell counts and had significantly lower high-density lipoprotein cholesterol levels than the group with a median LAN intensity <10 lux. In addition, the groups with median LAN intensities ≥3 and ≥10 lux had significantly higher odds ratios for sleep disturbances and depressive symptoms than the group with <3 and <10 lux, respectively. Therefore, the present study provided real-world data on bedroom LAN levels as a marker for indoor light pollution in a large sample and suggested that higher bedroom LAN levels are significantly associated with parameters of obesity, dyslipidemia, systemic inflammation, sleep disturbances, and depressive symptoms.

Investigation of the Effect of Solar Panel Temperature on Power Output Efficiency in Brass, Nigeria.

Background: Luminous efficacy is a property of light sources, which indicates what portion of the emitted electromagnetic radiation is usable for human vision relative to the overall efficiency of a light source for illumination. This also applies to solar panels. Purpose: To confirm the possibility of using solar panel as an alternative source of generating electricity and to highlight hindrances to the maximization of solar panel efficiency in the Niger Delta region of Nigeria using Brass as a case study. Materials and Methods: A Modern digital instrument, BK precision model 615 digital light meter and Alda AVD890C digital multimeter, were use for measurement of solar radiation, current and voltage respectively, under varying conditions of temperature. Result: An average Solar panel temperature of 26.2 oC was recorded in the morning hours. Towards noon, solar panel temperature increased up to 45 0C. Output current also increased from 0.0 to 20.0 x 10-1A. Solar panel temperatures between 26oC and 45oC appeared to favour increase in output current. Above 45oC, output current began to drop despite further increase in solar panel temperature. The best solar panel operating temperature in Brass is 45oC. Between the solar panel temperatures of 26oC and 32oC, output voltage remained relatively stable varying between 8.0V and 8.10V. Conclusion: Within limits, solar panel efficiency appears to be temperature dependent up to a maximum temperature, increasing up to 87.0% at 43.8oC. Higher temperatures appear to be counterproductive on solar panel efficiency.

Evaluation of Artificial Lighting in the Hospitals of Tehran University of Medical Sciences and the Satisfaction of the Medical Staff in 1400

Introduction: One of the important factors in providing safety and preventing stress in medical staff and patients referred to hospitals at night is the provision of standard lighting in the hospital. This study aims to determine the mean score of area artificial lighting and compare it with the standard in the hospitals of Tehran University of Medical Sciences and the satisfaction of the medical staff.&#x0D; Methods: In this cross-sectional study (descriptive-analytical), the intensity of general lighting at night was checked and compared with standard values based on the proposed models of the North American Society of Lighting Engineers using a lux meter, in Sina, Imam Khomeini, and Shariati hospitals of Tehran University of Medical Sciences. The satisfaction of the emergency medical staff with the lighting of the hospital area was assessed by a short researcher-made questionnaire. Descriptive and analytical statistics of the data were provided by SPSS software, version 22.&#x0D; Results: Based on the results of this study, the mean and standard deviation of lighting in Sina, Imam Khomeini, and Shariati hospitals were 33.12 ± 47.84, 24.67 ± 54.51, and 6.73 ± 10.87, respectively. The results showed that 55.4% of night shift staff were not satisfied with the area lighting. The mean score of lighting of the general hospital area (19.19 lux) was significantly different from the standard of hospital area lighting (50 lux) (PV = 0.000).&#x0D; Conclusion: The results of this study showed that the mean score lighting of the hospitals area was significantly lower than the lighting standard and the need to improve lighting systems is emphasized.

Subjective and objective evaluation of the impact of a quality assurance program on computer displays

Objective To examine impact of a quality assurance (QA) program for computer displays. Study design Five commercial off-the-shelf (COTS) displays (Dell Ultrasharp, 32-inch) were used in this study. The SMPTE test pattern was displayed on each monitor and three observers scored its pattern visibility. Screen luminance from select areas on the test pattern were measured with a Gossen light meter (MAVOLUX 5032B) to record maximum (Lmax), minimum (Lmin) and at 30%, 50% and 60% luminance. Next, display brightness and contrast were adjusted to enhance subjective perception of the SMPTE pattern. Screen luminance was measured as described above. Ambient illuminance was recorded at the center of the display. Results The ambient luminance was 0.05 cd/m2. The SMPTE pattern was adequately visualized on only 1 of the 5 displays. Overall, there was minimal variation in Lmin (0 to 0.3 cd/m2) and wide range in Lmax (59 to 339 cd/m2). The ambience ratio was 0.25 to 0.5 (recommended = 0.25). Display adjustment to optimally visualize the SMPTE contrast regions resulted in a decrease in the Lmax range (59 to 178 cd/m2, recommended maximum 250 cd/m2). Notably, brightness-contrast settings had to be customized for each display to optimally view the test pattern. Conclusions This study of high-end COTS displays used for radiologic diagnosis found that most displays required adjustment to optimally view the SMPTE test pattern. This underscores the need to establish a display QA program, as recommended by ADA/ANSI Standard 1094 and AAPM Report 270. Optimal visualization of the SMPTE test pattern required individualized display brightness and contrast controls that could not be simply applied to all monitors, emphasizing the need for periodic monitoring of individual displays. In ongoing studies, we are expanding our analyses to different display models and to ambient lighting settings that are more typical of chair-side settings. Statement of Ethical Review Ethical Review or exemption was not warranted for this study To examine impact of a quality assurance (QA) program for computer displays. Five commercial off-the-shelf (COTS) displays (Dell Ultrasharp, 32-inch) were used in this study. The SMPTE test pattern was displayed on each monitor and three observers scored its pattern visibility. Screen luminance from select areas on the test pattern were measured with a Gossen light meter (MAVOLUX 5032B) to record maximum (Lmax), minimum (Lmin) and at 30%, 50% and 60% luminance. Next, display brightness and contrast were adjusted to enhance subjective perception of the SMPTE pattern. Screen luminance was measured as described above. Ambient illuminance was recorded at the center of the display. The ambient luminance was 0.05 cd/m2. The SMPTE pattern was adequately visualized on only 1 of the 5 displays. Overall, there was minimal variation in Lmin (0 to 0.3 cd/m2) and wide range in Lmax (59 to 339 cd/m2). The ambience ratio was 0.25 to 0.5 (recommended = 0.25). Display adjustment to optimally visualize the SMPTE contrast regions resulted in a decrease in the Lmax range (59 to 178 cd/m2, recommended maximum 250 cd/m2). Notably, brightness-contrast settings had to be customized for each display to optimally view the test pattern. This study of high-end COTS displays used for radiologic diagnosis found that most displays required adjustment to optimally view the SMPTE test pattern. This underscores the need to establish a display QA program, as recommended by ADA/ANSI Standard 1094 and AAPM Report 270. Optimal visualization of the SMPTE test pattern required individualized display brightness and contrast controls that could not be simply applied to all monitors, emphasizing the need for periodic monitoring of individual displays. In ongoing studies, we are expanding our analyses to different display models and to ambient lighting settings that are more typical of chair-side settings.

Quality Of Lighting In Regular And Fullday Class Tsanawiyah Miftahul Huda Tayu Pati

An analysis of the quality of the lighting level in the classroom needs to be carried out to determine the existing lighting level. If the level of lighting is below the specified standard, it can cause eye damage. Meanwhile, if the level of lighting is above the standard, the classroom will be too bright. The purpose of this study was to determine the level of lighting in the Regular and Full Day classroom of MTs. Miftahul Huda Tayu. The tools and materials used in this experiment are lux meter, roller meter and thermohygro. The experiment was carried out in the Regular class school building and the Full Day classroom building with a sample of three rooms per building with each room representing each floor. The experiment was carried out during the day for three consecutive days. There are two types of the intensity measured in this experiment, namely natural intensity (lights off) and natural artificial intensity (lights on). In each room, 9 points were taken. The floor area and window area were measured using a roller meter. From the experiments that have been carried out, it can be concluded that the lighting in the Regular class (17-73 lux) and Full Day class (97-181 lux) buildings do not meet Indonesian National standards (Standar Nasional Indonesia, SNI).

Study of Length of Time to Reach Heat Unit due to Various Volumes and Frequencies of Watering in Garlic Plant (Allium sativum L.)

Garlic is one of the important horticultural commodities in Indonesia which is widely used its tubers as a cooking and medicinal ingredient. The large number of land conversion activities and competition between horticultural crops in the highlands have led to the development of garlic plants directed to lower land with different environmental conditions. The aim of this research is to study the volume and frequency of watering to length of time to reach heat unit of garlic. The research was carried out in February-May 2020 at the Greenhouse of the Faculty of Agriculture, Brawijaya University in Jatimulyo, Lowokwaru, Malang. The tools used are polybags, hoe, measuring cup, knife, tape measure, leaf area meter, camera, treatment board, stationery, lux meter, alcohol thermometer and thermohigrometer. The materials used are Lumbuh Putih variety, soil, and NPK fertilizer. This research was compiled with Split Plot Design with volume of watering as a main plot: J1: 400 mm / season, J2: 600 mm / season, J3: 800 mm / season, and J4: 1000 mm / season, while the frequency watering as a sub-plot: P1: watering once a day, P2: watering once every 2 days, and P3: watering once every 3 days. Total combination of treatments from the two factors was 12 treatments, each treatment repeated 3 times, so there were 36 experimental plots. Each experimental plot consist of 15 plants so there were 540 plants in total. Data observations were analyzed using the F test. If there is an interaction or effect of the treatment, a further test is carried out using the HSD test at 5% level. The results of J4 and P1 treatments required a longer time to reach the heat unit for each phase of garlic plant growth.

Archimedes' Principle Applied to Buoy Design for Measuring Purposes in Offshore Illumination Conditions

Solar cells are becoming so common that every industry except PLN is already using them to produce alternative energy. The more solar cells used, the more light intensity meters are needed to calculate the amount of Illumination in a given area. This research entails constructing or implementing software, calculating the float's balance against the impact of waves, and determining how the float distributes load using the Archimedes principle. Electrical construction and chassis buoyancy are included in the design. When the density of water is greater than the density of the object, namely &gt; objects (997 kg/m3 &gt; 46.73 kg/m3), the variables obtained are the total weight of the buoy of 5,044 kg with the distribution of the object force of 49.43 N and the buoyant force of 1046.08 N. then this design produces the required buoyancy force when manufactured and used.

Complaints of Computer Vision Syndrome in Telemarketing Workers at Bank X in Jakarta

Introduction: Computer Vision Syndrome (CVS) or digital eye strain is a collection of eye problems related to vision. The telemarketing division in Bank X has 10 hours working time per day and 60 hours per week. This study aimed to determine CVS complaints among telemarketing workers and analyze the factors that caused CVS complaints in workers. Methods: The study used a cross-sectional study design, with a total sample of 53 workers. The variables studied were lighting intensity, monitor distance, age, refractive disorders, eye rest, and eye protection. The study used a lux meter to measure the light intensity and the Snellen chart to see eye refraction abnormalities. Results: The results determined that 77.4% of computer workers in Bank X Telemarketing division experienced CVS complaints while 22.6% did not experience CVS. The results of statistical tests showed that light intensity, monitor distance, refractive disorders, and eye rest were associated with CVS complaints, while age and eye protection equipment were not related to CVS complaints. Conclusion: Most telemarketing workers experienced CVS complaints caused by lighting intensity, monitor distance, refractive disorders, and eye rest.

The Effect of Lighting Intensity on Visual Comfort in The Sacred Space Of Buddhist Temple

A Buddhist temple is a sacred Buddhist space where the building users require certain visual comfort conditions. The issue is that the temple's architectural style varies according to the local context and the type of belief it teaches. Implementing certain architectural styles will affect the interior space's artificial lighting design, which eventually affects the visual comfort of building users. Therefore, this study aims to determine the effect of artificial lighting on the building user's visual comfort in two different temple case studies that use dissimilar architectural styles in Medan City, Indonesia. Two data collection methods were used in this study. The first was by measuring the room's illumination level using a handheld lux meter. Secondly, through a survey/ questionnaire to find out user's perception of visual comfort related to the usage of artificial lighting during two activities in the sacred space in the temple: praying and reciting the Sutras. As a result, the two temples were identified using almost the same principle of applying artificial lighting, which aligns with Buddhism's purpose of enlightenment, 'the journey from dark to light.' The data collection results also show similar results. Both have illumination levels below the number stated in the visual comfort standards. While on the contrary, the majority of survey respondents from both cases felt visually comfortable during their activities in the case study. This study proves that the lighting design capable of providing positive visual impacts for users can rely on the technique and method of applying lighting distribution.

On the use of sniffers for spectrum occupancy measurements of Bluetooth low energy primary channels

The methods usually employed to measure channel occupancy show limitations in the context of Bluetooth Low Energy (BLE) advertisements. We propose and analyze the use of BLE sniffers as light and portable low-cost spectrum occupancy meters to be used in scenarios where real time signal analyzers are not adequate. For the measurement technique to be successful, several low-level effects must be considered. The paper argues about on-air time, receiving blind times due to processing and intra system interference, buffer saturation and frequency anchoring. Hence, a compensation procedure based on collision rate estimation is proposed. Results with the refined method show that occupancies of 40% can be measured with an overestimation error whose percentile 95% is 5 percentage points. This is reduced to 1.9 points when the occupancy is 15%. The sniffers perform in real time and are shown to correctly track short term load variations. The strategy has been successfully used to characterize occupancy in highly variable and loaded scenarios such as subway platforms and a shopping mall. Values up to 25% have been observed, which implies a relevant packet error rate. Hence, the tool can be used to make agile audits and configure the parameters that control communication redundancy in new or existing networks.

Hybrid Lighting System for Indoor Crop Production

Lighting systems for indoor crop production facilities face consistency, quality of lighting, and energy efficiency challenges. In this work, these challenges were addressed by developing a natural light collection system that allows sunlight to be concentrated and transmitted via optical conduits into the growing areas of an indoor crop production facility and supplementing it with artificial lighting. The daily light integral (DLI) estimator measures the natural light received while the supplemental lighting provides the additional photosynthetic photon flux to achieve the crop’s lighting requirements. Lux meter and spectrometer characterized the light sensors used to ensure accurate light measurements. The proposed system obtained a mean relative error of 1.78% between the DLI estimator and light instruments. In one testing activity, the system had collected 13.64 mol·m-2·d-1, while the artificial lighting supplemented 6.53 mol·m-2·d-1. The proposed system is vital in maintaining the DLI required by crops throughout the day.